Use gnulib set_nonblocking_flag function instead of fcntl.

The previous code:

  fcntl (fd, F_SETFL, O_NONBLOCK)

was technically incorrect, because it would have reset any
other flags on the file descriptor.

Thanks: Eric Blake

bootstrap

@@ -75,6 +75,7 @@ mkdtemp
 mkstemps
 netdb
 netinet_in
+nonblocking
 openat
 perror
 pipe2

daemon/inotify.c

@@ -29,6 +29,8 @@
 #include <sys/inotify.h>
 #endif
 
+#include "nonblocking.h"
+
 #include "guestfs_protocol.h"
 #include "daemon.h"
 #include "actions.h"
@@ -112,8 +114,8 @@ do_inotify_init (int max_events)
     reply_with_perror ("inotify_init");
     return -1;
   }
-  if (fcntl (inotify_fd, F_SETFL, O_NONBLOCK) == -1) {
-    reply_with_perror ("fcntl: O_NONBLOCK");
+  if (set_nonblocking_flag (inotify_fd, 1) == -1) {
+    reply_with_perror ("set_nonblocking_flag");
     close (inotify_fd);
     inotify_fd = -1;
     return -1;

lib/conn-socket.c

@@ -37,6 +37,7 @@
 #include <libintl.h>
 
 #include "ignore-value.h"
+#include "nonblocking.h"
 
 #include "guestfs.h"
 #include "guestfs-internal.h"
@@ -129,8 +130,8 @@ accept_connection (guestfs_h *g, struct connection *connv)
   conn->daemon_sock = sock;
 
   /* Make sure the new socket is non-blocking. */
-  if (fcntl (conn->daemon_sock, F_SETFL, O_NONBLOCK) == -1) {
-    perrorf (g, "accept_connection: fcntl");
+  if (set_nonblocking_flag (conn->daemon_sock, 1) == -1) {
+    perrorf (g, "accept_connection: set_nonblocking_flag");
     return -1;
   }
 
@@ -438,14 +439,14 @@ guestfs_int_new_conn_socket_listening (guestfs_h *g,
 
   assert (daemon_accept_sock >= 0);
 
-  if (fcntl (daemon_accept_sock, F_SETFL, O_NONBLOCK) == -1) {
-    perrorf (g, "new_conn_socket_listening: fcntl");
+  if (set_nonblocking_flag (daemon_accept_sock, 1) == -1) {
+    perrorf (g, "new_conn_socket_listening: set_nonblocking_flag");
     return NULL;
   }
 
   if (console_sock >= 0) {
-    if (fcntl (console_sock, F_SETFL, O_NONBLOCK) == -1) {
-      perrorf (g, "new_conn_socket_listening: fcntl");
+    if (set_nonblocking_flag (console_sock, 1) == -1) {
+      perrorf (g, "new_conn_socket_listening: set_nonblocking_flag");
       return NULL;
     }
   }
@@ -478,14 +479,14 @@ guestfs_int_new_conn_socket_connected (guestfs_h *g,
 
   assert (daemon_sock >= 0);
 
-  if (fcntl (daemon_sock, F_SETFL, O_NONBLOCK) == -1) {
-    perrorf (g, "new_conn_socket_connected: fcntl");
+  if (set_nonblocking_flag (daemon_sock, 1) == -1) {
+    perrorf (g, "new_conn_socket_connected: set_nonblocking_flag");
     return NULL;
   }
 
   if (console_sock >= 0) {
-    if (fcntl (console_sock, F_SETFL, O_NONBLOCK) == -1) {
-      perrorf (g, "new_conn_socket_connected: fcntl");
+    if (set_nonblocking_flag (console_sock, 1) == -1) {
+      perrorf (g, "new_conn_socket_connected: set_nonblocking_flag");
       return NULL;
     }
   }

m4/.gitignore

@@ -41,6 +41,7 @@
 /exponentd.m4
 /extensions.m4
 /extern-inline.m4
+/fatal-signal.m4
 /fchdir.m4
 /fclose.m4
 /fcntl_h.m4
@@ -156,6 +157,7 @@
 /netdb_h.m4
 /netinet_in_h.m4
 /nocrash.m4
+/nonblocking.m4
 /off_t.m4
 /onceonly.m4
 /openat.m4
@@ -165,6 +167,7 @@
 /perror.m4
 /pipe2.m4
 /pipe.m4
+/posix_spawn.m4
 /pread.m4
 /printf.m4
 /priv-set.m4
@@ -186,12 +189,14 @@
 /safe-read.m4
 /safe-write.m4
 /save-cwd.m4
+/sched_h.m4
 /secure_getenv.m4
 /select.m4
 /servent.m4
 /setenv.m4
 /setlocale.m4
 /sigaction.m4
+/sig_atomic_t.m4
 /signalblocking.m4
 /signal_h.m4
 /signed.m4
@@ -202,6 +207,7 @@
 /sockets.m4
 /socklen.m4
 /sockpfaf.m4
+/spawn_h.m4
 /ssize_t.m4
 /stat.m4
 /stat-time.m4
@@ -256,6 +262,9 @@
 /utimes.m4
 /vasnprintf.m4
 /vasprintf.m4
+/vsnprintf.m4
+/waitpid.m4
+/wait-process.m4
 /warnings.m4
 /warn-on-use.m4
 /wchar_h.m4